1. FIELD OF THE INVENTION
The present invention relates to an image-forming process, more particularly, to an image-forming process which controls fog generated in an intensification step and controls the influence of an intensification inhibitor.
2. DESCRIPTION OF THE PRIOR ART
There are known many processes for intensifying image formation by development and intensification processing of a silver halide light-sensitive material.
Oxidation of a p-phenylenediamine color developing agent through decomposition of hydrogen peroxide on the surface of a silver catalyst in the presence of a color former and subsequent dye formation by coupling with a color former (this phenomenon being called color intensification) are described, for example, in Friedman; History of Color Photography, 2nd, Ed., p.406 (1956).
Also, various other photographic processes utilizing the decomposition of peroxides on the surface of a noble metal surface are described in West German Pat. Nos. (OLS) 1,813,920, 1,950,102, 1,955,901, 1,961,029, 2,044,833, 2,044,993, 2,056,360, 2,056,359, 2,120,091, etc.
On the other hand, it has long been known that peroxides are decomposed on the surface of noble metals. Many examples are given in "Schokubai Kogaku Koza", Vol. 2 (1966, published by Chijin Shokan).
Color intensification processes using cobalt comples salts on the surface of noble metals are described in, for example, Japanese Patent Applications Nos. (OPI) 9,728/73, 9,729/73, 48,130/73, 84,229/74, 84,239/74, 84,249/74, 97,614/74, 102,340/74, 102,341/74, etc.
In addition, color intensification processing using halogenous acids such as a chlorite or the like is described in Japanese Patent Applications Nos. 128,327/74 and 139,917/74.
These compounds, e.g., peroxides, halogenous acids, cobalt (III) complex compounds, etc., having an intensifying action are called intensifying agents, and a processing bath containing these intensifying agents is called an intensifying bath.
In the process of using these intensifying agents, noble metals such as silver function as catalysts. The catalytic activity (i.e., intensifying effect) of the noble metals is seriously deteriorated by poisoning with compounds of ions which strongly adsorb onto the surface of the catalysts. For example, "Shokubai Kogaku Koza", Vol. 2, pp.272 - 296 (published by Chijun Shokan in 1966) describes that the decomposition of peroxides on noble metals is inhibited by H.sub.2 S, HCN, HgCl.sub.2, Hg(CN).sub.2, I.sub.2, NH.sub.2 OH, C.sub.6 H.sub.5 NH.sub.2, etc. These compounds also inhibit intensification with halogenous acids on a catalyst like metallic silver.
In the step of developing silver halide photographic light-sensitive materials, the intensifying effect of halogenous acids and peroxides is inhibited. This inhibition might be due to bromide ion or iodide ion, being released from silver halide during developing a photographic light-sensitive silver halide material and adsorbed on the surface of silver deposits to exhibit a catalyst poisoning effect.
Further, in order to prevent fog, raise the contrast of photographic materials and maintain the activity of a solution for continuous use at a definite level, bromide ion is often added to a developer in a proportion of about 0.1 - 10 g/liter. The bromide ion can be carried into an intensifying bath to cause a catalyst poisoning effect. Oxidation of a reducing agent (e.g., color developing agent, etc.) with an intensifying agent on the thus poisoned catalytic silver is so inhibited that an effective intensifying effect cannot be achieved. Such compounds are referred to as intensification-depressing compounds.
In the case of using cobalt (III) complex salt, the intensifying effect is depressed by a mercapto group containing compound or by iodine as is described in Japanese Patent Application (Laid Open) 9,728/73.
Since an intensifying agent causes oxidation of a reducing agent on only a slight amount of metallic silver catalyst, it is practically preferred to conduct the processing in a short time. Since a color developing agent incorporated in a film of color light-sensitive material with a developer is oxidized in a subsequent intensifying solution, a slow oxidation reaction would permit the color developing agent in the film to diifuse into the intensifying solution, resulting in an insufficient color density.
The above-described three intensifying agents satisfy this requirement, and intensifying solution thereof snow high activity. Therefore, fog is liable to be produced in non-image areas also. It may thus be considered one could control fogging by an antifogging agent being present in the step of oxidizing a reducing agent (e.g., color developing agent, etc.) by an intensifying agent on a catalyst.
In this case, however, not all known antifogging agents are effective, and effective ones are limited to those which have a specific structure. Further, the presence of such antifogging compounds promotes the poisoning action of compounds which poison the aforesaid catalysts (intensification-depressing compounds) or of ions, as compared with the case where such antifogging agents are absent, the intensifying effect thus being seriously inhibited.